Model genomes: The benefits of analysing homologous human and mouse sequences

Advances in the Human Genome Project. A review

While celebrating its fifth official birthday last year it seems that the Human Genome Project (HGP) has and will continue to yield important biochemical information to mankind. It is exhilarating to think about the transition from studying genome structure to understanding genome function. The collective actions of information dessimination, technology development for efficient and faster sequencing, high-volume sequencing and developing model organisms has led to its success sofar. Various genome-wide STS-based human maps were completed in 1995, including a genetic map, a YAC map, a RH map with, and an integrated YAC-RH genetic map. These maps provide comprehensive frameworks for positioning additional loci, with the current genetic and RH maps spanning essentially 100% of the human genome and the YAC maps covering 95%. Few genes, however, have yet been localized on these framework maps. To date the Human Genome Project has experienced gratifying success. The technology and data produced by the genome project will provide a strong stimulus to broad areas of biological research and biotechnology. However, enormous challenges remain.

Searching for regulatory elements in human noncoding sequences

Important progress has been made in the past two years in the identification of Pol II promoters. For most other regulatory elements, however, current biological knowledge is still insufficient to allow the development of prediction tools. The phylogenetic-footprinting strategy, which is based on the comparative analysis of homologous sequences, is a very efficient approach to identify new unknown regulatory elements. The recent organization of large-scale sequencing projects for some model vertebrate organisms will be extremely valuable for the prediction of regulatory elements in the human genome.

Striking sequence similarity over almost 100 kilobases of human and mouse T-cell receptor DNA

We report here the comparative DNA sequence analysis of nearly 100 kilobases of contiguous DNA in the C delta to C alpha region of the alpha/delta T cell receptor loci (TCRAC/TCRDC) of mouse and man. This analysis--the largest genomic sequence comparison so far--provides new insights into the functions of the T cell receptor genes as well as the surrounding chromosome structure through the identification of actively conserved DNA sequences. In this comparison we have identified a very high level of organizational and noncoding sequence similarity (approximately 71%) in contrast to previous findings in the beta-globin gene cluster. This observation begins to question the notion that much of the chromosomal non-coding sequence is junk.